What class $self refers to is dependend on the caller, not the package it's in, this is especially true if you have subclasses:

#!perl
C::A->thing(); # prints "C::A";
C::B->thing(); # prints "C::B";

package C::A;
sub thing {
  print shift;
}

package C::B;
use base 'C::A';
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There is a bug in your code:

my $self = @_; #2
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will set $self to the number of arguments to the anonymous sub, so this will not be what you want.

#3 $self->{bla} - $self will be the $self created when the argument to Class::B->do_things is called. Where that is, I can't tell, because there is no definition of Class::B->do_things in this code.

By the way, none of the variables are in package Class::B, because lexicals are not bound to classes anyway.

Hope this helps
Joost